U.S. Pat. No. 2,207,453 discloses an airplane wing having a main wing and two auxiliary wings. The rear auxiliary wing is rotatably connected to the front auxiliary wing about a first rotation axis that runs transversely to the direction of flight. The front auxiliary wing is rotatably connected to a rear end of a slidable rail about a second rotation axis. The slidable rail can be moved relative to the main wing in a slidable manner between a retracted position and an extended position. A selection mechanism of levers, rods, guide rails, pivotal connections and slidable connections is used to select different modes of operation of the auxiliary wings. In the retracted position of the slidable rail, the front auxiliary wing is in a fixed angular position, and the rear auxiliary wing can be rotated relative to the front auxiliary wing. Thus, the rear auxiliary wing can be used as aileron. When the slidable rail has been moved to its extended position, the front auxiliary wing may also be held in a fixed angular position, and the rear auxiliary wing may be rotated relative to the front auxiliary wing, or the front and rear auxiliary wings may be rotated together in order to control the rolling movement of the airplane. Furthermore, with the slidable rail in its extended position, it is possible for the front and rear auxiliary wings to be rotated in opposite directions. Thus, the front and rear auxiliary wings may be rotated about their rotation axes in a mutually dependent manner.
The second auxiliary wing at the rear of the first auxiliary wing, and the selection mechanism of levers, rods, guide rails, pivotal connections and slidable connections are complicated, generally unreliable and relatively heavy. In addition, the selection mechanism in its retracted position protrudes below the main wing, which causes increased drag and a higher risk of damage, for example by bird impacts.